Abstract: Based on the FLUENT software， different permutations and combinations of square cylinders are used to simulate the flow around frame dolphin pier structure， and get the resistance coefficients and the three dimensional flow field of each square column with different spacing ratios， and explore the law of the flow force distribution on the structure. The calculation results show that the square column resistance changes regularly in series and tied for simply two columns. When two rows of three square columns are used， the first row of the square columns blocks the water remarkably. The parameters of the flow around the square columns in the sharp corners position are symmetric， the resistance of each square column increases obviously， but haphazard. When the fluctuation cross arm spacing is 3 d， it has a little effect on each other. The resistance coefficient of cross arm is basically the same in the first row at the upstream， and the flow resistance of lateral cross arm of the second row decreases obviously. The flow resistance of the vertical support can be neglected. The flow resistance of the vertical cross arm can be ignored with the flow in the same direction.